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Thread: 12.04 new install - wifi fast after boot, then slows down

  1. #1
    Join Date
    May 2006

    12.04 new install - wifi fast after boot, then slows down

    Hi All,

    I have just upgraded (fresh install) from 10.04 where I also had this issue with this card. Not sure exactly which manufacturer but its one of the recommended ralink rt2500 chipsets. It is a pci card plugged into my desktop machine, running the 64 bit version of 12.04.

    The problem is when I first boot the computer, I get good wifi speeds as measured using This is on a new broadband connection, and speeds over wifi for my laptop register a steady 8mbits. Some time shortly after booting the desktop however, speeds drop to around a tenth of this, and sometimes drop even lower to 2-3kb/s, whilst the laptop still reports steady high speeds. I don't know if its a configuration issue, some kind of buffer filling up or something, or a problem with driver, but I would love to get it sorted! Possibly related to this posted in 2009 but vague and no resolution

    Any ideas greatly appreciated, output of relevent commands below

    root@hunter:~# lspci | grep Network
    04:04.0 Network controller: Ralink corp. RT2500 Wireless 802.11bg (rev 01)
    root@hunter:~# iwconfig
    lo        no wireless extensions.
    wlan0     IEEE 802.11bg  ESSID:"AAISP.NET-BROADBAND-22504"  
              Mode:Managed  Frequency:2.412 GHz  Access Point: 58:98:35:92:14:33   
              Bit Rate=48 Mb/s   Tx-Power=20 dBm   
              Retry  long limit:7   RTS thr:off   Fragment thr:off
              Encryption key:off
              Power Management:off
              Link Quality=33/70  Signal level=-77 dBm  
              Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
              Tx excessive retries:7  Invalid misc:55   Missed beacon:0
    eth0      no wireless extensions.
    root@hunter:~# ifconfig wlan0
    wlan0     Link encap:Ethernet  HWaddr 00:0e:2e:52:1d:7f  
              inet addr:  Bcast:  Mask:
              inet6 addr: 2001:8b0:88e:a594:f126:e058:9097:636a/64 Scope:Global
              inet6 addr: 2001:8b0:88e:a594:20e:2eff:fe52:1d7f/64 Scope:Global
              inet6 addr: fe80::20e:2eff:fe52:1d7f/64 Scope:Link
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:286781 errors:0 dropped:0 overruns:0 frame:0
              TX packets:204072 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000 
              RX bytes:348770655 (348.7 MB)  TX bytes:26483606 (26.4 MB)
    root@hunter:~# lsmod | grep rt2500
    rt2500pci              27646  0 
    rt2x00pci              14577  1 rt2500pci
    rt2x00lib              55301  2 rt2500pci,rt2x00pci
    eeprom_93cx6           12725  1 rt2500pci
    root@hunter:~# dmesg | grep rt2500
    [    5.797203] rt2500pci 0000:04:04.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
    [    5.834183] Registered led device: rt2500pci-phy0::radio
    [    5.834205] Registered led device: rt2500pci-phy0::quality
    root@hunter:~# lshw -C network
           description: Ethernet interface
           product: VT6102 [Rhine-II]
           vendor: VIA Technologies, Inc.
           physical id: 12
           bus info: pci@0000:00:12.0
           logical name: eth0
           version: 7c
           serial: 00:1a:92:3a:07:af
           size: 10Mbit/s
           capacity: 100Mbit/s
           width: 32 bits
           clock: 33MHz
           capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
           configuration: autonegotiation=on broadcast=yes driver=via-rhine driverversion=1.5.0 duplex=half latency=32 link=no maxlatency=8 mingnt=3 multicast=yes port=MII speed=10Mbit/s
           resources: irq:23 ioport:d000(size=256) memory:dfffe000-dfffe0ff
           description: Wireless interface
           product: RT2500 Wireless 802.11bg
           vendor: Ralink corp.
           physical id: 4
           bus info: pci@0000:04:04.0
           logical name: wlan0
           version: 01
           serial: 00:0e:2e:52:1d:7f
           width: 32 bits
           clock: 33MHz
           capabilities: pm bus_master cap_list ethernet physical wireless
           configuration: broadcast=yes driver=rt2500pci driverversion=3.2.0-23-generic firmware=N/A ip= latency=32 link=yes multicast=yes wireless=IEEE 802.11bg
           resources: irq:18 memory:dfdfe000-dfdfffff
    root@hunter:~# iwlist scan
    lo        Interface doesn't support scanning.
    wlan0     Scan completed :
              Cell 01 - Address: 58:98:35:92:14:33
                        Frequency:2.412 GHz (Channel 1)
                        Quality=42/70  Signal level=-68 dBm  
                        Encryption key:on
                        Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
                                  24 Mb/s; 36 Mb/s; 54 Mb/s
                        Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 48 Mb/s
                        Extra: Last beacon: 52ms ago
                        IE: Unknown: 001941414953502E4E45542D42524F414442414E442D3232353034
                        IE: Unknown: 010882848B962430486C
                        IE: Unknown: 030101
                        IE: Unknown: 2A0100
                        IE: Unknown: 2F0100
                        IE: IEEE 802.11i/WPA2 Version 1
                            Group Cipher : TKIP
                            Pairwise Ciphers (1) : CCMP
                            Authentication Suites (1) : PSK
                        IE: Unknown: 32040C121860
                        IE: Unknown: 2D1A1E181BFFFF000001000000000000000000000000000000000000
                        IE: Unknown: 3D1601051300000000000000000000000000000000000000
                        IE: Unknown: 4A0E14000A002C01C800140005001900
                        IE: Unknown: 7F0101
                        IE: Unknown: DD940050F204104A0001101044000102103B00010310470010327F7AADBB665F7CA10E01EC94FE564C1021000B546563686E69636F6C6F721023000E546563686E69636F6C6F72205447102400043538326E104200093132303856464737331054000800060050F204000110110012546563686E69636F6C6F722054473538326E100800020004103C0001011049000600372A000120
                        IE: Unknown: DD090010180201000C0000
                        IE: WPA Version 1
                            Group Cipher : TKIP
                            Pairwise Ciphers (1) : TKIP
                            Authentication Suites (1) : PSK
                        IE: Unknown: DD180050F2020101000003A4000027A4000042435E0062322F00
    eth0      Interface doesn't support scanning.
    root@hunter:~# lsb_release -d
    Description:	Ubuntu 12.04 LTS
    root@hunter:~# uname -mr
    3.2.0-23-generic x86_64
    root@hunter:~# /etc/init.d/networking restart
     * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces
     * Reconfiguring network interfaces...                                                                               [ OK ]

  2. #2
    Join Date
    Feb 2008
    Ubuntu Mate 16.04 Xenial Xerus

    Re: 12.04 new install - wifi fast after boot, then slows down

    Hi, please set your wireless settings to match the screenshots and see if that helps:

    Also your link quality is low, how far are you from the router? is there walls or anything in between the computer and the router?

    Also I suggest going into your router settings and changing the channel to 1 or 11 and see if that helps.
    Last edited by wildmanne39; February 10th, 2013 at 06:57 PM.

  3. #3
    Join Date
    May 2006

    Re: 12.04 new install - wifi fast after boot, then slows down

    Thanks for the quick reply

    Tried the network settings as you suggested, on restarting the network interface it was fast again briefly, but quickly dropped back down to 0.8mbps. As for the channel and signal strength - the laptop copes ok in very simlar situation and the signal strength does not fluctuate with the speed. Also found this post which seems related!

  4. #4
    Join Date
    Feb 2008
    Ubuntu Mate 16.04 Xenial Xerus

    Re: 12.04 new install - wifi fast after boot, then slows down

    Hi, the fact is that this driver is not the best supported these days and it is hard to get decent speeds out of it.

    You could try:
    sudo iwconfig wlan0 rate 54M
    that may help a little or compile a newer driver from the manufacturer's website but it probably will not help, my best suggestion is to break down and by a new adapter.

    Also you could try removing the special characters in your SSID I am surprised that you can connect at all with them in there.
    Last edited by wildmanne39; June 27th, 2012 at 02:29 AM.

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